The present disclosure relates to a display unit such as an organic electroluminescence unit and an electronic apparatus including such a display unit.
In recent years, development of display units (organic electroluminescence (EL) displays) using an organic EL device has been advanced. The display units are broadly divided into a top emission system and a bottom emission system.
In a top emission organic EL display unit, as an electrode (an upper electrode) where light is extracted, a transparent conductive film configured of a metal oxide film such as indium tin oxide (ITO) is typically used. Moreover, in order to connect the upper electrode to an external circuit or the like, a wiring connection section (a connection section) is provided as a so-called cathode contact in a predetermined region of a drive substrate including a pixel circuit. The upper electrode is so formed as to establish interlayer connection with the connection section, and a lead wire configured to connect the connection section and the external circuit or the like to each other is provided in the drive substrate.
However, the above-described transparent conductive film is typically formed with use of a physical vapor deposition (PVD) method such as a sputtering method. Therefore, the connection section is easily oxidized by oxygen or oxygen plasma during film formation. Consequently, it is difficult to use, for the connection section, a metal that exhibits insulation properties in oxide form. More specifically, it is difficult for aluminum (Al), an alloy (Al—Nd alloy) of aluminum and neodymium (Nd), or the like to function as an electrode, since contact resistance thereof is increased by oxidation.
Therefore, as the connection section, a connection section configured by laminating a metal film made of molybdenum, titanium, or the like on a surface of an Al—Nd alloy (or aluminum) is used. Since titanium and molybdenum exhibit electrical conductivity even in oxidized form, the connection section is allowed to secure electrical connection with the upper electrode. However, the connection section may be eroded during etching of another electrode or the like, and the connection section may not secure sufficient electrical connection accordingly. Moreover, when a substrate size is increased, or when in-plane uniformity in etching processing is degraded, electrical connection may not be secured. This exerts a large influence on a lighting state.
In view of the above, for example, in Japanese Unexamined Patent Application Publication No. 2004-235078, there has been proposed a technique of decreasing resistance of an upper electrode (a transparent conductive film) by bringing a metal wire and the upper electrode into contact with each other, and then performing heating treatment. Thus, contact resistance between the upper electrode and the connection section is allowed to be reduced, thereby obtaining electrical connection therebetween.